Re: [PATCH] perf tools: Don't use brace expansion.

[Bernd Petrovitsch <bernd@sysprog.at>]

On Die, 2010-08-17 at 12:42 -0300, Arnaldo Carvalho de Melo wrote:
> Em Tue, Aug 17, 2010 at 01:58:00PM +0200, Bernd Petrovitsch escreveu:
[...]
> > The following patch below at the end works for me. Alas, it is against
> > vanilla main line.
> 
> Adding $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h there, to have it look:
>
> +# we compile into subdirectories. if the target directory is not the source directory, they might not exists. So
> +# we depend the various files onto their directories.
> +$(LIB_OBJS) $(BUILTIN_OBJS) $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h: $(sort $(dir $(LIB_OBJS) $(BUILTIN_OBJS)))

Hmm, that adds that $(OUTPUT)PERF-VERSION-FILE and
$(OUTPUT)common-cmds.h (also) depends on the subdirectories of the other
objects (and thus it works always because at least one of them is a
subdirectory of $(OUTPUT)).
To be 110% anal, it should look like e.g.
+$(LIB_OBJS) $(BUILTIN_OBJS) $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h: $(sort $(dir $(LIB_OBJS) $(BUILTIN_OBJS)) $(OUTPUT))

or actually all targets.

> +# In the second step, we make a rule to actually create these directories
> +$(sort $(dir $(LIB_OBJS) $(BUILTIN_OBJS))):
> +       mkdir -p $@ 2>/dev/null
> +

BTW there is no automatic variable or other make-construct to refer in
the dependencies on the own target. Therefore the copy-paste-the-
variables solution.

Perhaps an additional variable reduces clutter (and eases maintenance)?

+# we compile into subdirectories. if the target directory is not the source directory, they might not exists. So
+# we depend the various files onto their directories.
+DIRECTORY_DEPS = $(LIB_OBJS) $(BUILTIN_OBJS) $(OUTPUT)PERF-VERSION-FILE $(OUTPUT)common-cmds.h
+$(DIRECTORY_DEPS): $(sort $(dir $(DIRECTORY_DEPS)))
+# In the second step, we make a rule to actually create these directories
+$(sort $(dir $(DIRECTORY_DEPS))):
+       mkdir -p $@ 2>/dev/null
+

That should guarantee that all directories from the targets are created.

> As it was failing when I did:
> 
> rm -rf ~/build/perf
> make -C tools/perf O=~/build/perf
> 
> With that it retains the existing functionality,

Ah, I `mkdir`ed the output directory explicitly before the `make` (and
after the `rm -rf`).


BTW which is the preferred tree to base patches on (for the "perf"
subsystem)?

	Bernd
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